CPU Tuner allows you to monitor and tweak your CPU's performance. Customize the settings for your CPU governor, underclock to save battery, overclock to improve performance, and set various trigger-based performance profiles to ensure your CPU performs just the way you want. Again, a little care and research as to what your hardware can tolerate is important, especially if you choose to overclock. Also, unlike similar applications (SetCPU, for example), CPU Tuner is free on the Google Play market.